Political money has poured into Wisconsin in recent months, not for the presidential or Senate races but for a state vote getting national billing as a battle for the interests of the middle class. On one side are conservatives from across the country who back Republican Governor Scott Walker, a darling of the right since his 2011 crusade to rein in government spending by eliminating most collective bargaining rights for public employees. On the other are Democrats and union backers conducting a grassroots drive to collect more than a million signatures in a heated campaign to recall Walker.

Republicans say checks on union power are essential to curb government spending and protect the middle class, on whom higher taxes fall disproportionately. Democrats portray the Wisconsin law – which also requires public workers to pay more for their pensions and healthcare – as a move to undermine workers' protections that they say helped build the middle class, in favor of the wealthy.

The fight is expected to cost as much as $70 million, and Walker has not been shy about asking for contributions. Last week, he took his message to Washington, telling attendees at the Conservative Political Action Conference "we need your help financially." "Just one dollar, one dollar can be another phone call made. It can be another flier printed. It can be a piece of a radio or TV ad. Every bit counts," he said.

As Walker spoke, a $700,000 advertising campaign sponsored by Americans for Prosperity (AFP), a foundation funded by conservative billionaire brothers Charles and David Koch of oil and gas conglomerate Koch Industries, hit the Wisconsin airwaves, the latest phase of its "Stand with Walker" campaign. The ad does not mention the governor by name, but argues that the state's collective bargaining clamp-down has saved money and jobs. An AFP spokesman said the ad's aim was to focus on issues, not the officials involved.

Walker's most recent fundraising will not be made public until later this spring when the date is set for the recall vote. Since the beginning of 2011 he has raised $12 million. His donors include leading conservative funders like Houston homebuilder Bob Perry, a major donor to presidential SuperPacs and a fund to elect conservatives to Congress, who thus far has given $500,000 to the Walker recall fight. Hedge fund founder Bruce Kovner, a former chairman of the American Enterprise Institute, kicked in $100,000 and Trevor Rees-Jones, chief executive of Dallas-based Chief Oil & Gas, also gave $100,000. Perry, Kovner and Rees-Jones did not respond to calls.

The influx of out-of-state money has heightened tensions between anti-Walker forces and groups affiliated with the small-government Tea Party movement that are doing much of the grassroots organizing on Walker's behalf. "He (Walker) appears more concerned with serving big pocket out of state donors and less concerned about the millions of people his special interest policies impact here in Wisconsin," said Ryan Lawler, a board member of United Wisconsin, one of the groups leading the recall effort.

The out-of-state money also signals the importance of this race in a year dominated by presidential politics. Democratic President Barack Obama carried Wisconsin by 13 points in 2008, but that was before Walker and the Republican-led legislature stirred up grassroots anger over government spending. Now the state is considered a toss-up, and many political experts believe the Walker recall fight will help determine the winner in the presidential contest.

Charles Franklin, a visiting professor of law and public policy at Marquette University Law School, said that while many Wisconsinites are passionate about ousting Walker, "it is unknown whether that can translate into passion for electing Obama. That is an open question at this point."

A Million Voices

Walker was elected in 2010 on a wave of voter disenchantment with Obama and concern over state and local government spending. Backed by a Republican-dominated legislature, his solution was to take on the public employee unions with a bill to curb collective bargaining rights. The issue sparked a national firestorm, and Walker managed to push the bill through. Democrats challenged the measure's legality, but a Republican dominated state Supreme Court upheld it in June 2011. Activists on both sides then mobilized to try to shake up the legislature. Pro-union activists targeted six Republicans for recall, and Tea Party activists singled out three Democrats. The recall efforts cost $44 million, well over double the funding for 116 state races in 2010, with the money split fairly evenly between conservative donors and labor unions. Two Republican incumbents lost, but Republicans kept Senate control.

Walker foes then turned their attention to unseating the governor. Across the state, 30,000 volunteers collected signatures on a recall petition that also targets Lieutenant Governor Rebecca Kleefisch and four Republican senators. "We came together because what Walker did was wrong for Wisconsin," said United Wisconsin's Lawler, 35. "This recall election is more important than all the others combined."

To defend Walker, Tea Party activists cranked up a grassroots campaign. The number of Tea Party groups in the state doubled to 140 in 2011, part of a strategy to cover the entire state and boost conservative voter turnout. "This year is going to be like last year on steroids," said Tim Dake of Wisconsin Grandsons of Liberty, a Tea Party group.

Tea Party groups and the state Republican Party have separate initiatives to independently verify signatures on the petition, which could take months. Nearly 11,000 volunteers have signed up for the Tea Party groups' online effort to cross-check the names against public records more quickly. "Whether you like it not, Wisconsin law allows for recalls," said Ross Brown of We the People of the Republic, a Tea Party group. "Even though we may not find enough problems to challenge the recall, we want to bring integrity to the process."

Activists like Bonnie Ketterhagen of newly-formed Tea Party group, We Vote Burlington, say that once a vote is set she and others will get out the voters. "We have to stop the spending and the borrowing," she said, pointing to a stack of "I Stand With Walker" yard signs at her husband's office in downtown Burlington. "When the time comes, we'll be ready to defend him. And beyond the recall, we'll be ready for November."

The Democratic Party said that while it has focused on logistics and fundraising for the recall campaign, anti-Walker grassroots groups will continue the fight into the general election in November. "They know Wisconsin faces the same political battle as the rest of the country," said Graeme Zielinski, a spokesman for the Wisconsin Democratic Party. "They know this is about protecting America's middle class."